Ever since the mysterious three-eyed woman showed up with the cloaked girl and small boy who could turn into aliens, there had been lots of more tourism to the Plaza. And of the largest tourist group were a bunch of aliens known as the Crystal Gems. Most of the plaza noticed that there was a boy around KO's age that got along with him, and their parents seemed to get along too…
It was the topic of discussion when the two weren't around, and most of the plaza weren't aware of Gar's and Carol's relationship. Some would openly discuss it with one of Gar's close friends, Mr. Logic. Not that he minded. He knew that logically, they would not end up together. Gar and Carol loved eath other too much to let each other go again, and from how Greg talked about his deceased wife, he would most likely never love another woman like that again.
Still the boys enjoyed each others company, and enjoyed having a parent that they were comfortable talking to about how they taught their children.
As for the other Gems, they usually kept to themselves, only interacting with Steven and who ever he brought over to meet them.